1. Field of the Invention
The subject invention relates to an air conditioning system, and more specifically, to a method of operating a directed relief valve to ventilate a refrigerant from the air conditioning system.
2. Description of the Prior Art
Air conditioning systems with directed relief valves for ventilating refrigerant are well known in the art. An example of such a system is disclosed in the U.S. Pat. No. 6,085,531 (the '531 patent) to Numoto et al.
The '531 patent discloses an air conditioning system utilizing a flammable refrigerant, such as propane. The system includes the standard components of a compressor, a condenser, an expansion device, and an evaporator. The system also includes a sensor to continuously monitor leakage of the refrigerant, particularly in an air space. When a leak is detected, the sensor generates a signal. A directed relief valve receives the signal and opens the valve in response to the signal to ventilate the refrigerant to the surrounding atmosphere.
The U.S. Pat. No. 6,912,860 (the '860 patent) to Zima et al. discloses another air conditioning system utilizing a potentially toxic or flammable refrigerant and includes the same standard components and a sensor to continuously monitor leakage of the refrigerant. The '860 patent additionally discloses a method for checking proper sensor operation. When a single sensor is utilized and a malfunction is determined, a controller generates a malfunction signal to be sent to the operator, and the system ventilates the refrigerant to the surrounding atmosphere. In the event that less than all of the plurality of sensors show a malfunction when a plurality of sensors are utilized, a controller generates a malfunction signal to be sent to the operator without ventilating the refrigerant. However, in the event that all of the plurality of sensors indicate a malfunction, the controller generates a malfunction signal and actually ventilates the refrigerant to the surrounding atmosphere.
Although the prior art air conditioning systems continuously monitor refrigerant leakage and proper sensor operation to allow for ventilation of a refrigerant to the atmosphere in case of a refrigerant leak or sensor malfunction, there remains the need for an air conditioning system that is more fail-safe and/or operative over a wide range of vehicle operating conditions.